JP2003042721A - Method and apparatus for measurement of film thickness of thin film as well as method of manufacturing device by using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method and an apparatus of manufacturing a high-accuracy thin-film device wherein the film thickness of a transparent film being worked and the distribution of the film thickness are measured with high accuracy, the film thickness on the outermost surface is measured with high accuracy during a CMP working operation, without being influenced by the distribution of the film thickness in an LSI region generated in the CMP working operation or inside a semiconductor wafer face, and the film thickness can be controlled with high accuracy. SOLUTION: A visual field and a measuring position which are used to measure the film thickness of the transparent film being worked are measured by an area which is not influenced by the distribution of the film thickness of an CMP-worked actual device pattern. A comparatively flat region is specified on the basis of the reflected light intensity, the frequency spectrum intensity or the like in a feature amount of spectral reflected light from the transparent film, the film thickness is measured, and the film thickness is controlled with high accuracy. Consequently, a flattening working operation in a CMP working process based on the distribution of the film thickness can be optimized, a film formation condition to a film formation process and a working condition in an etching process can be optimized, and the semiconductor device is manufactured with high accuracy.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing a semiconductor device by measuring the thickness and thickness distribution of a transparent film and controlling the film thickness. For example, a manufacturing line for manufacturing a semiconductor device on a silicon wafer. Then, in the flattening treatment step of the surface after film formation, the method of measuring the outermost surface film thickness of the wafer, and by measuring the film thickness, the flattening treatment step is managed to manufacture the semiconductor device. In addition to the above, examples of the transparent film include a resist film and an insulating film in the manufacturing process of thin film devices such as DVD, TFT, and LSI reticle.

[0002]

2. Description of the Related Art For example, a semiconductor device is manufactured by forming a device and a wiring pattern on a silicon wafer by film formation, exposure and etching.
In recent years, in order to realize high precision and high density, the trend toward miniaturization and multi-layering has been advanced. As a result, the unevenness of the wafer surface is increased. Since such unevenness on the wafer makes it difficult to expose the wafer, which is indispensable for forming wiring and the like, the surface of the wafer is flattened.

As this flattening process, a method (CMP: Chemical Mechanical Polishing) of polishing the surface by chemical and physical actions to realize flattening is used. CMP is a processing method known in the art.

An important issue in CMP processing is film thickness control. In particular, by measuring the film thickness during CMP processing and incorporating an in-situ measurement system into the CMP processing system, the processing is terminated when the film is processed to a predetermined film thickness, and highly accurate flatness and film thickness variation are reduced. It is necessary to. Therefore, various methods have been proposed as in-situ measurement techniques. JP-A-6-252113 and JP-A-9-7985 disclose an in-situ measurement system capable of measuring the film thickness on an actual device pattern (a fine circuit pattern of an actual product). There is. In Japanese Laid-Open Patent Publication No. 6-252113, the spectral distribution of the interference light due to the white light film is frequency analyzed to measure the film thickness on the actual device pattern, and attention is paid to the relationship between the frequency component of the spectral distribution waveform and the film thickness. Calculate the absolute thickness.
On the other hand, in Japanese Unexamined Patent Publication No. 10-83977, a change in the interference light intensity of laser (single wavelength) light due to a transparent film due to processing time is detected, and the film thickness is calculated from the frequency component of the waveform.

Further, Japanese Unexamined Patent Publication No. 10-294297 and Japanese Unexamined Patent Publication No. 2000-77371 disclose techniques for specifying a measurement position and performing in-situ measurement. Japanese Unexamined Patent Publication No. 10-294297 discloses extracting a characteristic of an image of a circuit pattern or forming a diffraction grating in a scribe area of the pattern to specify a measurement position. JP-A-2000-77
In Japanese Patent Laid-Open No. 371, paying attention to the maximum value and the minimum value of the spectral waveform, the measurement position is specified from the maximum value and the minimum value of the already measured spectral waveform and the comparison process, and the film thickness during processing is measured. .

[0006]

Generally, in the film thickness control by the processing time of CMP, the polishing amount (polishing rate) per unit time varies, and the ratio of filling in the plane of the pattern formed on the wafer (hereinafter, Since the polishing rate varies depending on the pattern area ratio), it is difficult to control the film thickness with high accuracy. FIG. 17 is a schematic diagram of the inventors
It is the film thickness distribution measurement result of the semiconductor device measured using the technique disclosed in Japanese Patent Laid-Open No. 0-310512. FIG. 17
Is a film thickness distribution measurement result 160 of the transparent film (interlayer insulating film) in an area of about 20 mm of the wafer after CMP processing. Figure 1
7 is a wiring pattern portion 161, 162, a peripheral circuit portion 16
3. Boundary parts 164, 16 between the peripheral circuit part and the wiring pattern part
5 shows the film thickness distribution of No. 5. As can be seen from the film thickness distribution measurement result 160, the boundary parts 164 and 165 of the peripheral circuit part and the wiring pattern part are several square nm in a region of about 2 mm.
The film thickness has changed. On the other hand, the wiring pattern portion 16
1, 162 and the peripheral circuit portion 163 have a relatively flat film thickness in a region of several mm.

Since this film thickness distribution is caused by processing conditions such as the pattern area ratio, the type of polishing pad of the processing apparatus, the type of polishing liquid (slurry), etc., the type of semiconductor circuit pattern and processing conditions (polishing pad It depends on the consumption state and the slurry concentration), and it changes for each product or for each wafer. As described above, in-s during CMP processing
In the in-tu measurement, depending on the visual field region to be measured, a region in which the film thickness is greatly changed is measured, which causes a problem that the measurement accuracy is lowered. Further, as a method of specifying the measurement position, Japanese Patent Laid-Open No. 10-294297 and Japanese Patent Laid-Open No. 2000-2000
Although it is disclosed in Japanese Patent Laid-Open No. 77371, the measurement field of view is determined in a relatively large region (about φ2 mm) without paying attention to the measurement field of view in these publications, so that the film thickness distribution as shown in FIG. When measuring the state of, the measurement accuracy may be reduced. That is, the spectral waveform is waveform data including information from a wide area where the underlying wiring state and film thickness are different, and it is difficult to specify a desired measurement position. For this reason, in the CMP process, the processing cannot be finished at the time when the film is processed to have a predetermined film thickness, and highly accurate flatness and film thickness variation cannot be reduced, so that highly accurate film thickness management can be performed. It is difficult and the yield of semiconductor devices is reduced. Further, conventionally, a slurry has been used as a polishing liquid in the CMP processing step.

As disclosed in Japanese Unexamined Patent Publication No. 10-83977, a transparent window is formed in a polishing pad to extract a spectral waveform from the wafer surface in the slurry and in-
In-situ measurement is performed. Since the slurry is a polishing liquid containing particles such as silica and potassium hydroxide, it is optically translucent and has a low transmittance. In addition, during use, the transparent window is processed by particles contained in the polishing liquid to form frosted glass-like irregularities, the spectral reflectance from the wafer surface is significantly reduced, and the spectral measurement cannot be stabilized. However, there is also a problem that the processing is terminated at the time when the film is processed into a predetermined film thickness, and it becomes difficult to control the film thickness with high accuracy.

An object of the present invention is to change the thickness of a transparent film to CM.
An object of the present invention is to provide a method and an apparatus therefor capable of performing highly accurate measurement during CMP processing without being affected by a film thickness distribution of an LSI region generated by P processing, a thin film device manufacturing method using the same, and a manufacturing apparatus therefor. And

It is another object of the present invention to provide a method and a method for measuring the film thickness of a transparent film with high accuracy during CMP processing without being affected by the film thickness distribution in the wafer surface which occurs during CMP processing. An object is to provide an apparatus, a method for manufacturing a thin film device using the apparatus, and an apparatus for manufacturing the same.

Another object of the present invention is to set the thickness of a transparent film during CMP processing without being affected by the film thickness distribution in the LSI region and the wafer surface thickness distribution that occur during CMP processing. It is an object of the present invention to provide a method and an apparatus therefor capable of measuring with high accuracy in the measurement visual field, a method for manufacturing a thin film device using the method and an apparatus for manufacturing the same. Another object of the present invention is to change the thickness of the transparent film to the LS produced by CMP processing.
Method and device for identifying a desired measurement position during CMP processing with high accuracy without being affected by the film thickness distribution in the I region and the film thickness distribution in the wafer surface, and its apparatus, and a thin film device using the same It is an object of the present invention to provide a manufacturing method and a manufacturing apparatus therefor.

Another object of the present invention is to set the thickness of the transparent film during CMP processing without being affected by the film thickness distribution in the LSI region and the film thickness distribution in the wafer surface which occur during CMP processing. High-precision thin-film device manufacturing by using the film thickness measurement result of high-precision measurement by specifying the measurement field of view and the desired measurement position for the process conditions of the manufacturing process (etching, film formation, etc.) after the CMP processing process. It is an object of the present invention to provide a method and a manufacturing apparatus thereof.

Another object of the present invention is to extract a spectral waveform having a high S / N ratio during CMP processing without affecting the thickness of the transparent film by the deterioration of the spectral transmission characteristics of the slurry caused by CMP processing. It is an object of the present invention to provide a method and an apparatus therefor capable of performing highly accurate measurement, and a method and an apparatus for manufacturing a thin film device using the same.

According to the present invention, the film thickness of the transparent film is not affected by the film thickness distribution of the LSI region generated by the CMP processing, and the accuracy is, for example, ± several 10 nm or less on the actual device pattern during the CMP processing. An object of the present invention is to provide a measurable method and an apparatus thereof, a thin film device manufacturing method using the same, and a manufacturing apparatus thereof. As an example thereof, the measurement technique disclosed in Japanese Patent Laid-Open No. 2000-310512 is used to measure the outermost surface film thickness on the actual device pattern after CMP processing to extract the film thickness distribution in the LSI region. Then, the measurement field of view and the measurement position are determined based on the result of the film thickness distribution, the desired measurement field of view from the device pattern during CMP processing, and the spectral waveform from the measurement position are extracted to determine the maximum during CMP processing. It is an object of the present invention to provide a method and an apparatus that enable highly accurate film thickness management by measuring a surface film thickness with high accuracy, and a method and an apparatus that realize an improvement in process throughput.

[0015]

In order to achieve the above object, according to the present invention, the field of view and the measurement position for measuring the film thickness of the transparent film during CMP processing are the LSI area of the actual device pattern processed by CMP. It is determined based on the measurement result of the film thickness distribution in. A technique for measuring an actual device pattern uses a film thickness measuring method (hereinafter referred to as an actual pattern film thickness measuring method) as disclosed in JP 2000-310512 A developed by the inventors. The film thickness distribution of the device pattern is measured, and the desired measurement visual field is determined based on the measurement result. From the measurement result example of FIG.
A sharp change in film thickness (1 mm
It is desirable to have a field of view that can secure high-precision measurement accuracy even if the thickness changes by several 100 nm. When the film thickness distribution is flat in the LSI region, the measurement visual field may be increased to several mm.

Regarding the measurement position, it is desirable to measure the film thickness of the relatively flat regions 161 and 162 shown in FIG. 17 in order to realize highly accurate measurement. Areas 161 and 162 are wiring circuit pattern portions, and since the wiring pattern density of the base under the transparent film is about several tens% and stable, C
This is a region with good flatness even in MP processing. Also, in the semiconductor manufacturing process, it is desirable to control the film thickness of the wiring circuit formation region, which is a wiring formation region for forming contact holes and the like and connecting layers between layers, and for determining etching conditions and the like. In the determination of the measurement position in the present invention, (1) the intensity difference of the spectral reflection light is extracted. (2) Extract the frequency spectrum intensity of the spectrally reflected light. (3) Compare with the spectral waveform measured by the actual pattern film thickness measuring method. And the like.

According to this method, the film thickness at each position is selected by selecting the measurement position from the feature amount of the spectral waveform from the peripheral circuit portion of the LSI, the scribe area, or the like, not limited to the wiring formation region. Can be managed.

Although the measurement field and the measurement position in the LSI area (expressed as a chip area) formed on the semiconductor wafer have been described above, the film thickness can be controlled within the wafer surface. In CMP processing, a wafer is processed while rotating and oscillating. According to the present invention, the orientation flat position and the notch position of the wafer are held in a state of being roughly positioned on the wafer holder, and the in-situ film thickness measurement during the CMP processing is performed based on the orientation flat position and the notch position instruction information of the wafer from the wafer holder. It is determined whether the measurement position of the system is the central portion or the peripheral portion of the wafer, the measurement is performed, and the measurement result is output.

Further, according to the present invention, since the spectral waveform on the wafer surface is measured at a high S / N with the optically opaque slurry interposed, pure water or the like is optically transparent in the vicinity of the spectral waveform measurement window. A liquid is supplied to dilute the slurry so that spectroscopic measurement can be performed. The material of the transparent window used for the spectral waveform measurement window is a material close to the spectral refractive index of the slurry,
The increase in reflectance (improvement of spectral transmittance) due to the difference in refractive index at the interface between the slurry and the transparent window is reduced. Therefore, the precision of the film thickness management is improved by extracting the high S / N spectral waveform even during the CMP processing.

[0020]

BEST MODE FOR CARRYING OUT THE INVENTION As an example of an embodiment of the present invention, the film thickness of a transparent film formed on a wafer surface during processing is targeted for a CMP process in manufacturing a semiconductor device,
During CMP processing, for example, several tens on the actual device pattern
An example applied to a method of measuring with accuracy within nm will be shown.

FIG. 1 shows an embodiment in which the film thickness control method of the present invention is applied to a CMP processing apparatus. In the CMP processing apparatus, a polishing pad 2 is formed on a polishing platen 1, and a holder 3 holds a wafer 4 to be processed. Further, on the polishing pad 2, a dresser 5 for dressing the surface of the pad is used to regularly dress the pad to keep the processing rate constant. The structure is such that the liquid slurry 6 in which the coating particles for polishing are mixed is supplied onto the polishing pad. In order to measure the film thickness during the CMP process, the measurement optical system 7 is configured to be able to measure the spectral waveform of the wafer surface from below the polishing table 1 and from the measurement window 8 provided in the polishing pad 2. The thickness of the measured spectral waveform is calculated by the film thickness measurement controller 9. The film thickness measurement controller 9 is connected to the actual pattern film thickness measurement device 10 so that the information from the actual pattern film thickness measurement device 10 can be obtained. The actual pattern film thickness measuring device 10 measures the film thickness distribution of a wafer in the same kind of process as the wafer 4 in advance by the measuring method disclosed in Japanese Patent Laid-Open No. 2000-310512. Based on the distribution measurement result, the measurement condition controller 11
At, the spectral field corresponding to the measurement visual field used in the measurement optical system 7 and the film thickness at each measurement position is selected and input to the film thickness measurement controller 9.

The wafer 4 rotates the polishing disk 1 in the direction of arrow A, and the holder 3 processes the entire surface of the wafer 4 while rotating the wafer in the direction of arrow B and oscillating in the direction of arrow C, and the dresser 5 also. The pad 2 is raised while periodically rotating in the direction of arrow D and swinging in the direction of arrow E. In the above configuration, when the polishing platen 1 rotates, the window glass 81 incorporated in the measurement window 8 passes on the measurement optical path 120 of the measurement optical system 7 every rotation of the polishing platen 1 to measure the spectral waveform of the wafer 4. The spectral waveform detected by the optical system 7 is input to the film thickness measurement controller 9 to calculate the film thickness at a desired measurement position.

FIG. 2 shows a detailed embodiment of the measuring optical system 7 and the film thickness measuring controller 9 of FIG. The measurement optical system 7 includes a detection lens 71, an illumination light source 72, a half mirror 73, a spatial filter 74, an imaging lens 75, a field stop unit 76, a field stop 761, a field stop 762, and a spectroscope 77. In the measurement optical system 7, white illumination light (wavelength of about 300 nm to 800 nm) is applied to the illumination light source by the half mirror 73 through the detection lens 71 and the window glass 81 to illuminate the wafer 4 being processed. The reflected light from the wafer 4 is reflected by the spatial filter 74, the imaging lens 75, and the field stop 761.
The light is guided to the spectroscope 77 through and is dispersed. The dispersed waveform signal is measured by the film thickness measurement controller 9, and the spectral waveform 91
The waveform correction process 92 for removing the influence of the waveform distortion due to the slurry described below is performed. From the spectral waveform whose waveform has been corrected
No. 000-310512 discloses a frequency / phase analysis measurement method or a pattern structure fitting measurement method, and a film thickness calculation 94 is performed on a device pattern being processed. Finish processing. Further, the measurement condition controller 11 inputs the measurement visual field information and the spectral waveform data based on the film thickness distribution from the actual pattern film thickness measuring device 10 to the film thickness controller 9.

The film thickness controller 9 determines whether or not the detected spectral waveform 91 is applied as film thickness measurement data, selects a spectral waveform required for measurement, and uses it for film thickness calculation. The measurement visual field is set as a parameter before the film thickness measurement is started, and the aperture unit 76 of the measurement optical system 7 is switched to determine the visual field aperture diameter to determine a desired measurement visual field. The spatial filter 74 of the measurement optical system 7 is the scattered light from the edge of the wiring pattern and the N.V. Since the high-order diffracted light caused by A can be removed, there is an effect of reducing the waveform distortion such as when the diffracted light causes a large distortion in the spectral waveform, and it is effective in improving the S / N of the spectral waveform.

FIG. 3 is a diagram for explaining the measurement visual field of this embodiment. The window glass 81 shown in FIG.
FIG. 9 is a schematic diagram showing an example in which the detection field of view is Φ50 to 100 μm, the field of view size is determined in consideration of the optical system magnification, and the spectral waveform is measured. The spectral waveform data at a plurality of positions on the wafer 4 are detected from the window glass 81 for one rotation of the polishing platen 1. Although the embodiment of FIG. 3 describes a state in which spectral data is extracted four times,
The more measurement points there are, the more accurate the film thickness can be evaluated. Actually, the measurement sampling number is determined from the number of revolutions of the polishing board 1 of the CMP machine, the size of the measurement window, the sampling speed of the spectroscope, the light amount of the illumination system, the reflected light from the wafer, and the like.
In the example shown in FIG. 3, the polishing platen 1 has a diameter Dφ of 250 mm, the rotation speed is 100 rpm, and the spectroscope 77 is sampled at a speed of 1.
If mms, the area of the width of φ50 μm × 0.4 mm is measured. Window glass 81 size 1 diameter
Even if it is 0 mm, it is possible to measure 10 times. That is, one rotation of the polishing platen selects a necessary spectral waveform from the spectral data of the wafer 4 at 10 positions and inputs it to the film thickness controller 9 to calculate the film thickness.

Next, the present invention will be described more specifically with reference to FIGS.

FIG. 4 shows an example of an LSI circuit (one chip). A wiring circuit pattern portion 41 is formed in the center of the LSI circuit 40, a regular wiring is partially formed in the memory circuit portion 42, and a peripheral circuit pattern portion 43 is formed around the wiring circuit pattern portion 41. FIG. 5 is a partially enlarged view of FIG. 4, showing the relationship between each wiring part and the visual field when measurement is performed in the measurement visual field φ100 μm. Figure 5
The wiring circuit pattern portion 410 is shown in (a), and the peripheral circuit pattern portion 430 is shown in (b).

In the recent LSI, the wiring pattern 411 is formed with a width of several μm to 0.1 μm, and the measurement visual field 412 is φ.
When the thickness is 100 μm, the area ratio of the pattern in the measurement visual field 412 is several tens%. On the other hand, the peripheral circuit patterns 431 and 433 are formed with a width of several tens of μm to several hundreds of μm, and when the measurement visual field 432 is φ100 μm, the area ratio of the pattern in the measurement visual field 412 is 50% to 100%.
%.

FIG. 6 shows the spectral reflection characteristics in the measurement visual field region shown in FIG. The spectral waveform 61 is the measurement visual field 41 of FIG.
2, the spectral waveform 62 is the measurement visual field 434 of FIG.
3 is a waveform when measured at the position of the measurement visual field 432 of FIG.

FIG. 7 shows the frequency spectrum characteristic of the measurement visual field region shown in FIG. That is, it can be seen from the spectral reflection characteristics that the spectral reflection characteristics differ depending on the area ratio of the base pattern portion to the measurement visual field. When the ratio of the area of the base pattern in the measurement visual field is large, the spectral reflectance is large, and when the area is small, the reflectance is small. This tendency is particularly remarkable in the long wavelength region where the wavelength is long. FIG. 7 shows the frequency spectrum characteristic of the measurement visual field region shown in FIG. 7A shows the frequency spectrum characteristic of the wiring circuit portion, FIG. 7B shows the memory circuit portion, and FIG. 7C shows the frequency spectrum characteristic of the peripheral circuit portion. Since the spectral characteristics differ depending on the shape of the wiring pattern occupying the measurement visual field, it can be seen that the measurement position can be specified also from the frequency spectrum of the spectral waveform.

Since the characteristics of the spectral waveforms shown in FIGS. 6 and 7 are reproducible in the respective wiring parts, based on the spectral waveform data of the actual pattern film thickness measuring device 10 shown in FIG. The measurement position can be specified by comparing and evaluating similar spectral waveforms, reflectances, frequency spectra, and the like.

FIG. 8 shows a schematic view of a semiconductor wafer. FIG. 9 is an example of a film thickness distribution measurement result obtained by measuring the film thickness distribution of the central chip 82 and the peripheral chip 83 of FIG. 8 with the actual pattern film thickness measuring device 10. In the measurement result of the central chip in FIG. 8, the middle part is slightly hot and the peripheral part is thinly distributed. FIG. 9 (a)
Is flat as compared with (b). The film thickness at the outermost periphery 95 of the chip in FIG. 9B is extremely thin. Since no pattern is formed on the outermost periphery 96 of the chip, it is considered that the processing rate becomes large and thin in the CMP processing step.

In the embodiment shown in FIG. 8, if the substantially central regions 92 and 93 of the chip can be specified as the measurement positions during the CMP processing, the state of the film thickness on the entire surface of the wafer can be controlled with high accuracy. That is, the wiring circuit pattern portion 412 that is relatively flattened as shown in FIG. 5 is specified, and the film thickness is measured for each chip in the wafer surface. Can be managed. The measurement of the film thickness distribution in the wafer surface according to the present invention is performed by measuring the film thickness distribution on the boundary portion between the peripheral circuit pattern portion and the wiring circuit pattern portion where the film thickness variation is large and the outer peripheral circuit portion where the film thickness variation is large as shown in FIG. There is an effect that either the relatively flat wiring circuit portion or the peripheral circuit pattern portion can be specified and measured.

Further, the spectral waveform of FIG. 6 is not an ideal sinusoidal waveform but a distorted waveform because the slurry 6 is interposed. Since the difference in refractive index between the transparent film and the slurry on the pattern is smaller than that of the transparent film and air, the waveform distortion is considered to be influenced by the reflection intensity of the underlying pattern below the transparent film. In FIG. 6, a curve 600 indicates distortion of the waveform.
Exists as the central trend component.

FIG. 10 shows a correction waveform extracted by adding and multiplying the spectral waveform of FIG. 6 with the central component as the waveform distortion coefficient from the envelope of each waveform in order to remove the trend of the spectral waveform of FIG. is there. In FIG. 10, the spectral waveform 91 is the spectral waveform 61 of FIG. 6, and the spectral waveform 92 is the spectral waveform 6 of FIG.
2. The spectral waveform 93 corresponds to the spectral waveform 63 of FIG. The method disclosed in Japanese Unexamined Patent Application Publication No. 2000-310512 may be used to remove the trend, and the film thickness can be calculated with high accuracy by calculating the film thickness from the waveform thus corrected for the spectral waveform.

FIG. 11 shows the spectral waveform of the wafer surface at high S /
It is explanatory drawing for measuring by N.

In FIG. 11, an optical material having a refractive index close to that of the slurry, for example, the window glass 81 of the embodiment shown in FIG.
Lithium fluoride (MgF2) with a refractive index of about 1.4
A window glass 101 made of magnesium fluoride (MgF2) or the like was used. Since the window glass 101 and the slurry 102 have almost the same refractive index, the reflectance component at each interface decreases, the intensity of the reflected light received by the spectroscope 77 increases, and the S / N of the spectral reflected light improves. Has the effect of In addition, the slurry 10 near the window glass 101
When pure water is locally supplied from the pure water tank 103 to the vicinity of 2 through the pipe 104, the slurry 102 is locally diluted, and the cloudy-slurry slurry solution becomes optically transparent with an abrasive or the like. When the reflected light on the wafer surface is detected through the optically transparent aqueous solution, the reflectance of the spectral waveform shown in FIG. 6 is improved, and the waveform distortion due to scattering from the abrasive in the slurry is also reduced. The spectral waveform is closer to a sine wave, and there is an effect that the accuracy of film thickness calculation is improved. The liquid to be supplied is not limited to pure water as long as it is a liquid that makes the slurry optically transparent.

12 and 13 are diagrams for explaining a method of controlling the film thickness distribution within the wafer surface by measuring the film thickness distribution over the entire surface of the wafer in the CMP processing step.

12 and 13, the description of the same structure and operation as in FIG. 2 will be omitted. In FIG. 12, a holder 113 is newly provided with a position sensor 111 and a rotation angle detector 1.
12 is provided, and a wafer position controller 121 that detects the information of each position and angle and calculates the measurement position is provided. Further, in order to detect the position of the measurement window 81 of the polishing board, a sensor 124 is provided near the optical axis 120 of the measurement optical system 7.

FIG. 12A shows the wafer 4 and the holder 113.
It is a figure which shows the alignment method of. A pre-alignment unit 117 including a rotatable wafer holder 114 that holds the wafer 4 and a notch sensor 115 that detects the notch of the wafer 4 is disposed below the holder 113. In the above configuration, the wafer holder 114 of the pre-alignment unit 117 is rotated, the notch sensor 115 detects the notch 116 of the wafer, and the wafer holder 113 is stopped.
Next, the holder 113 so as to maintain the relative relationship with the notch 116.
The wafer 4 is placed on the holding surface 113 a of the holder 113 so that the position sensor 111 of FIG. The wafer 4 held by the holding surface 113a of the holder 113 moves onto the polishing plate 1 of the CMP processing machine and starts polishing and flattening the wafer 4. FIG. 12B is a schematic view from the front of the CMP processing machine, and FIG. 12C shows a part of the plan view.

In FIG. 12, the outer shape L1 of the wafer 4, the distance L between the center of the polishing table 1 and the measurement optical axis 120 of the measurement optical system 7.
2. The distance L3 between the center of the polishing plate 1 and the holder 113 is a constant value. Since the holder 113 swings, the swing sensor 118 detects the swing amount L4 from the reference center. In this state, the angular position of the rotation detector 112 of the holder 113 is reset and CMP processing is started. When the sensor 124 detects the measurement start dog 123 and the wafer position controller 124 detects the measurement start signal, the measurement start position 111
The distance L2- of the measurement optical axis 120 from the center of the wafer 4 at a
L4 (calculate the positional relationship between the wafer center and the measurement center 120 from the measurement start dog 124 having a relative relationship with the wafer diameter L1 and the detected notch 116) and the rotation angle θ of the wafer 4 are determined, and the polishing table 1 is Each time the wafer is rotated, the wafer measurement position with respect to the film thickness based on the spectral waveform measured by the measurement optical system 7 is specified.

Therefore, it is possible to determine which chip at the center or the periphery of the wafer surface shown in FIG. 9 is being measured. For example, Sio2 of the correlation insulation film of the wafer is φ2 by CMP process.
When processing a 00 mm wafer, one rotation of the polishing plate (about 100
rpm) for several nm, and about 200 nm per minute. Since the film thickness measurement accuracy of the present embodiment can measure a film thickness change of several tens of nm, it is also possible to specify the measurement location for each rotation of the polishing platen, calculate the remaining film thickness, and display it. .

14 and 15 show the measurement display state of the remaining film thickness. FIG. 14 shows the residual film thickness of each chip, and FIG.
Indicates the remaining film thickness in the area of several chips. These results are output in real time during CMP processing, and the processing ends when the predetermined remaining film thickness is reached. 14 and 15
The measurement results shown in can be managed as the history of processed wafers. If the measurement results are attached to a wafer and used as the processing conditions in the next process, the throughput and product quality of the manufacturing process can be improved. Has the effect of

FIG. 16 shows a method of manufacturing a semiconductor device according to the present invention. In the method of manufacturing a semiconductor device according to the present invention, after a thin film is formed on the surface of the wafer 151 by the film forming apparatus 152 by sputtering or the like, the wafer is transferred to the CMP processing step 153. In the CMP processing step 153, the film thickness of the surface of the wafer 151 is controlled by the processing end point detection unit 155 in the same manner as described in the above embodiment, and the film thickness is processed to be flat using the CMP apparatus 154, and the cleaning is performed. After cleaning with the device 156, the film thickness measuring device 157 measures the film thickness of a desired portion of the wafer 151 as necessary. It should be noted that the film thickness measurement using the film thickness measuring device 157 does not necessarily have to be performed on all the wafers, and may be carried out by extracting one of several wafers if necessary. The wafer that has gone through the CMP processing step 153 is subjected to wiring processing and the like in the etching step 159 after passing through the exposure device step 158, and then carried to the next step.

According to the present invention, the film thickness in the CMP process can be measured during the CMP process, and the film thickness at a position on the wafer can be measured. The measurement result is used as a slurry condition (material, concentration, supply amount) of the CMP device 154, and a pad condition (material,
The flatness of the processed surface of the wafer can be significantly improved as compared with the conventional technique by feeding back to the CMP processing conditions such as the shape, the dress, the replacement time, etc.), the polishing rotation speed, the wafer supporting pressure and the like. By processing the wafer whose surface flatness is greatly improved by the CMP process in the subsequent exposure and etching steps, it becomes possible to form a fine pattern with high reliability. In addition, CMP is performed while controlling the film thickness according to the present invention.
It is also possible to attach the measurement result of the film thickness of the in-plane distribution to the processed wafer 151. By using the attached measurement results, it is possible to manufacture the high-quality semiconductor wafer 160 by optimally controlling the etching conditions (etching time, applied voltage, gas supply amount) and the like in the etching step 159.

[0046]

According to the present invention, it is possible to measure the film thickness of a transparent film of a semiconductor device which is being polished in the CMP process with high accuracy, and it is possible to control the polishing process with high accuracy based on the measured film thickness data. Become. Since it becomes possible to control the film thickness distribution within the silicon wafer (substrate) surface of the semiconductor device during polishing processing with high accuracy, the planarization processing in the CMP processing process based on the film thickness distribution is optimal. It is possible to optimize the film forming conditions in the film forming process and the processing conditions in the etching process, and it is possible to manufacture a highly accurate semiconductor device. In addition, it becomes possible to detect the end point with high accuracy in the CMP process in the method of manufacturing a semiconductor device on the silicon wafer and the manufacturing line, and it is possible to improve the throughput of the process.

[Brief description of drawings]

FIG. 1 is a perspective view showing a schematic configuration of a CMP polishing apparatus provided with a film thickness measuring device according to the present invention.

FIG. 2 is a perspective view showing a specific example of the configuration of a CMP polishing apparatus equipped with a film thickness measuring means according to the present invention.

FIG. 3 is a plan view of a polishing pad on which a wafer for explaining a measurement visual field according to the present invention is mounted.

FIG. 4 is a plan view of an LSI circuit pattern for semiconductor.

FIG. 5 is a plan view of a semiconductor LSI circuit pattern showing a detailed example of a semiconductor LSI circuit pattern and a measurement field of view.

FIG. 6 is a graph showing an example of spectral reflection characteristics from a circuit pattern according to the present invention.

FIG. 7 is a graph showing an example of spectral spectrum intensity characteristics from a circuit pattern according to the present invention.

FIG. 8 is a plan view of a semiconductor LSI wafer.

FIG. 9 is a perspective view showing an example of a film thickness distribution of a transparent film of a semiconductor LSI.

FIG. 10 is a front view showing an example of the structure of a detection window according to the present invention.

FIG. 11 is a graph showing spectral reflection characteristics for calculating a film thickness according to the present invention.

FIG. 12 (a) C having a film thickness measuring function according to the present invention
FIG. 3 is a front view of the MP processing apparatus, (b) a front view of the CMP processing apparatus according to the present invention, and (c) a plan view of a holder of the CMP processing apparatus.

FIG. 13 is a front view showing a schematic configuration of a CMP processing apparatus according to the present invention.

FIG. 14 is a front view of a display screen showing an example of a screen displaying a measurement result in the present invention.

FIG. 15 is a front view of a display screen showing an example of a screen displaying a measurement result in the present invention.

FIG. 16 is a process chart showing an example of a process for manufacturing a semiconductor device using the CMP processing system according to the present invention.

FIG. 17 is a perspective view of a semiconductor LSI showing an example of a film thickness distribution of a transparent film of the semiconductor LSI.

[Explanation of symbols]

1 …… Polishing machine 2 …… Polishing pad 3 …… Holder 4
...... Wafer 5 ...... Dresser 6 …… Slurry 7 …… Measurement optical system 8 …… Measurement window 9 …… Film thickness measurement controller 10 …… Actual pattern film thickness measurement device 11 …… Measurement condition controller 81 …… Window glass
71 …… Detection lens 72 …… Illumination light source 73 …… Half mirror 74 …… Spatial filter 74 …… Imaging lens 76 …… Aperture unit
761 …… Field diaphragm 762 …… Field diaphragm 763 ……
Measurement field of view 40 …… LSI circuit 41 …… Wiring circuit pattern section 42 …… Memory circuit section 43 …… Peripheral circuit pattern section 412 …… Measurement field of view 61, 62, 63 …… Spectral waveform
82 …… Center chip 83 …… Peripheral chips 92, 93
…… Chip center area 600 …… Waveform trend component
91, 92, 93 ... Spectral waveform after trend correction 101
…… Window glass 102 …… Slurry 103 ……
Pure water tank 104 …… Piping 111 …… Position sensor
112 …… Rotation angle detector 113 …… Holder 114 …… Wafer holder 115 …… Notch sensor 116 …… Notch 117 …… Pre-alignment part 113a …… Holding surface 120
…… Measurement optical axis 151 …… Wafer 152 …… Deposition equipment
153 …… CMP processing process 154 …… CMP machine 15
5 …… Machining end point detector 156 …… Cleaning device 157 ……
Film thickness measuring device 158 ... Exposure device 159 ... Etching process 151 ...
... Semiconductor wafer

Continued front page    (72) Inventor Keiya Saito             292 Yoshida-cho, Totsuka-ku, Yokohama-shi, Kanagawa             Inside the Hitachi, Ltd. production technology laboratory F term (reference) 2F065 AA30 BB03 BB17 BB22 CC02                       CC19 CC31 DD13 EE00 FF42                       FF51 GG02 HH04 LL22 LL30                       LL46 LL67 MM04 PP13 QQ33                       QQ44 UU07                 3C058 AC02 BA01 BA07 CB03 CB06                       DA12 DA17                 5F033 HH38 QQ48 XX01 XX03 XX37

Claims (16)

[Claims] 1. The surface of a sample on which an optically transparent thin film is being polished is irradiated with white light, the reflected light generated from the sample by the irradiation of the white light is detected, and the detected reflected light is spectroscopically analyzed. A method of obtaining the film thickness of the optically transparent film based on a waveform, detecting reflected light from an area determined based on a film thickness distribution measured in advance, and determining the spectral waveform of the detected reflected light. A method for measuring the thickness of a thin film, characterized in that the thickness of the transparent film is obtained based on the above. 2. The surface of a sample on which an optically transparent thin film is being polished is irradiated with white light, the reflected light generated from the sample by the irradiation of the white light is detected, and the detected reflected light is detected. A method of obtaining the film thickness of the optically transparent film based on a spectral waveform, based on the spectral waveform of the reflected light at a desired position based on the characteristic amount of the spectral waveform of the reflected light generated from the sample A method for measuring the thickness of a thin film, which comprises measuring the thin film. 3. The surface of a sample on which an optically transparent thin film is being polished is irradiated with white light, the reflected light generated from the sample by the irradiation of the white light is detected, and the detected reflected light is A method for obtaining the film thickness of the optically transparent film based on a spectral waveform, wherein the reflected light generated from the sample is detected by time division, and the characteristic amount of each spectral waveform detected by time division is detected. A method for measuring the thickness of a thin film, which comprises measuring the thin film based on a spectral waveform at a desired position based on. 4. The film thickness measuring method according to claim 2, wherein the characteristic amount of the detected reflected light is based on the reflected light intensity of the spectral waveform of the detected reflected light. 5. The film thickness measuring method according to claim 2, wherein the characteristic amount of the detected reflected light is based on the frequency spectrum intensity of the spectral waveform of the detected reflected light. 6. The film thickness measuring method according to claim 2, wherein the characteristic amount of the detected reflected light is similarity of a spectral waveform based on a film thickness distribution measured in advance. 7. The surface of a sample on which an optically transparent thin film is being polished is irradiated with white light, the reflected light generated from the sample by the irradiation of the white light is detected, and the detected reflected light is spectroscopically analyzed. A method for obtaining the film thickness of the optically transparent film based on a waveform, detecting reflected light from an area determined based on the film thickness distribution in the same step as the sample measured in advance, and detecting the reflected light. A method for measuring the thickness of a thin film, which comprises measuring the thin film based on the spectral waveform of the reflected light at a desired position based on the characteristic amount of the spectral waveform of the reflected light. 8. A white light is radiated while supplying an optically transparent fluid to the surface of a sample on which an optically transparent thin film is being polished, and the reflected light generated from the sample by the irradiation of the white light. Is detected and the film thickness of the optically transparent film is determined based on the detected spectral waveform of the reflected light. 9. The surface of the sample on which an optically transparent thin film is being polished is irradiated with white light, the reflected light generated from the sample by the irradiation of the white light is detected, and the detected reflected light is detected. In the method for determining the film thickness of the optically transparent film based on the spectral waveform, the reflected light generated from the sample is detected through an optical glass having a refractive index equivalent to that of a polishing liquid, A method for measuring the thickness of a thin film, characterized in that the film thickness of the optically transparent film is obtained based on the detected spectral waveform of the reflected light. 10. A means for irradiating the surface of a sample on which an optically transparent thin film is being polished with white light, a detection means for detecting the reflected light emitted from the sample by the irradiation means, and Means for determining the film thickness of the optically transparent film based on the spectral waveform of the reflected light detected by the detection means,
A means for determining a measurement area based on a film thickness distribution measured in advance and a means for calculating a film thickness of a transparent film based on a spectral waveform of reflected light generated from the measurement area are provided. Thin film thickness measuring device. 11. A means for irradiating the surface of a sample on which an optically transparent thin film is being polished with white light, a detecting means for detecting reflected light emitted from the sample and emitted from the sample, Means for determining the film thickness of the optically transparent film based on the spectral waveform of the reflected light detected by the detection means,
A thin film characterized by comprising: a means for extracting a characteristic amount of a spectral waveform of reflected light generated from the sample; and a means for calculating a film thickness of a transparent film at a desired position based on the characteristic amount. Film thickness measuring device. 12. A means for irradiating the surface of a sample on which an optically transparent thin film is being polished with white light, a detecting means for detecting reflected light emitted from the sample by the irradiation means, and Means for determining the film thickness of the optically transparent film based on the spectral waveform of the reflected light detected by the detection means,
A means for detecting the reflected light generated from the sample by time division, a means for extracting the characteristic amount of a plurality of spectral waveforms of the reflected light detected by the time division, and a means for detecting a desired position based on the characteristic amount. A film thickness measuring device for a thin film, comprising: means for calculating the film thickness of a transparent film. 13. In the step of polishing an optically transparent film formed on the surface of a thin film device, the optically transparent film is irradiated with white light, and the thin film device emits the white light. The reflected light is detected from an area determined based on the film thickness distribution of the thin film device in the same step as the thin film device measured in advance, and the optically transparent based on the spectral waveform of the detected reflected light. A method for manufacturing a thin film device, which comprises obtaining a uniform film thickness. 14. In the step of polishing an optically transparent film formed on the surface of a thin film device, the optically transparent film is irradiated with white light, and the thin film device emits the white light. The reflected light is detected, and the optically transparent film thickness is obtained based on the spectral waveform of the reflected light at a desired position based on the characteristic amount of the spectral waveform of the reflected light generated from the thin film device. Method for manufacturing thin film device. 15. In the step of polishing an optically transparent film formed on the surface of a thin film device, the optically transparent film is irradiated with white light, and the thin film device emits the white light. The reflected light is detected, the reflected light generated from the thin film device is detected by time division, and based on the spectral waveform of the reflected light at a desired position based on the characteristic amount of each spectral waveform detected by time division. A method for manufacturing a thin film device, characterized in that the optically transparent film thickness is obtained. 16. In the step of polishing an optically transparent film formed on the surface of a thin film device, the optically transparent film is irradiated with white light, and the thin film device emits the white light. The reflected light is detected, the reflected light generated from the thin film device is detected by time division, and based on the spectral waveform of the reflected light at a desired position based on the characteristic amount of each spectral waveform detected by time division. A method for manufacturing a thin film device, characterized in that the optically transparent film thickness is obtained.